A Heavy Anti-Aircraft Battery was sited at Fort Lytton during WW2. It consisted of four 3.7-inch heavy anti-aircraft guns. Each gun was in its own protective emplacement (gun pit) consisting of a polygonal concrete block wall with protective earth and rock piled around the outside. The four gun pits were sited around a command post. The command post contained instruments for estimating data such as aircraft range, height and direction, and an electro-mechanical computer (predictor) which calculated bearing, elevation and fuse-time for the guns.
The battery still exists in relatively good condition about 300m from the Fort Lytton Visitor Centre and inside the perimeter of the Caltex refinery. The above photo was taken in November 2015 and shows the four gun pits, the outside of each being covered in grass.
This Google satellite image was retrieved in October 2016 and shows all four gun pits. The command post is at the left (western edge) of the site and is largely obscured by a tree.
The following photographs are from the Australian War Memorial. They were taken at Fort Lytton on 11 November 1943 by Ronald Noel Keam, an official photographer. The gunners are from 385th Troop, 6th Australian Heavy Anti-Aircraft Battery.
OPERATING THE PREDICTOR IN THE COMMAND POST.
A detailed model of the site is on display in the Old Artillery Store building.